I had a 1989 E350 years ago that was fuel injected and had similar issues. It started with, while driving in hot weather, I would get a very strong gasoline smell. It was so strong that you were sure there was a lot of leaking fuel. I would stop and check everything and not find. any leaking gas! But when I unscrewed the gas cap, I got a loud whoosh of presure coming out of the filler neck. After that and not again until I would be driving in hot weather would it occur. Eventually things started getting really hot under the vehicle the propane tank pressure relief valve would shoot off a loud burst of gas for about 30 seconds and then eventually things would cool off and be okay. On this same trip, the ac condensing line came loose and shot all of the freon out. eventually the engine started acting up and I lost some power so that I could only go. 45 mph.
It turns out that one of the problems was the catalytic which had come apart and was partially plugged up which was causing the converter to overheat and run red hot.
I was told by a Ford mechanic that the 2 oxygen sensors were faulty and causing the failure of the catalytic converter which caused things around the vicinity to also overheat and fail.